GUANTANAMO BAY U.S. NAVAL BASE, Cuba, June 21 (Reuters) - An Arabic-English interpreter confused the al Qaeda magazine Inspire with the gentlemen's magazine Esquire during a pretrial hearing in the Guantanamo war crimes tribunal on Friday.

The mix-up came in a hearing for five prisoners who could face execution if convicted of launching the Sept. 11, 2001, hijacked plane attacks that killed 2,976 people and propelled the United States into a global war against al Qaeda.

A week-long hearing has focused on whether military and intelligence agents at the Guantanamo Bay U.S. Naval Base snooped into legal documents and attorney-client conversations that are supposed to be confidential. Defense attorneys said stringent restrictions on their communications had interfered with their attempts to prepare a defense.

The outgoing legal adviser for the Guantanamo detention operation, Navy Captain Thomas Welsh, testified that attorney-client mail was carefully screened to prevent the introduction of physical and informational contraband. He said the rules were tightened after a defense lawyer tried to send a copy of Inspire magazine to one of the defendants.

“I'm told that the translation is wrong,” interrupted defense attorney Cheryl Bormann, who was not the source of the intercepted magazine.

She said the interpreter translating Welsh's testimony for the defendants had identified the contraband publication to them as Esquire. That magazine describes its focus as “beautiful women, men's fashion, best music, drink recipes.”

Inspire magazine bills itself as the publication of Yemeni-based group al Qaeda in the Arabian Peninsula and famously published an article titled, “Make a bomb in the kitchen of your mom.” The United States considers it a propaganda and recruitment vehicle for the group, and killed its editor in a drone strike in Yemen last year.

“Do you know that al Qaeda is alleged to be a co-conspirator in this case? Did you reflect on the fact that many of these materials would be related to the defense?” asked defense attorney David Nevin, who also was not the source of the magazine.

Welsh said he was more concerned with Inspire's encouragement of attacks on U.S. personnel.

Mohammed and his four co-defendants are charged with crimes including conspiracy, hijacking and murder and are expected to go to trial in late 2014 at the earliest. (Editing by Peter Cooney)